Miniature pneumatic device

ABSTRACT

A miniature pneumatic device includes a miniature fluid control device and a miniature valve device. The miniature fluid control device includes a gas inlet plate, a resonance plate, a piezoelectric actuator and a gas collecting plate. A first chamber is formed between the resonance plate and the piezoelectric actuator. After a gas is fed into the gas inlet plate, the gas is transferred to the first chamber through the resonance plate and then transferred downwardly. Consequently, a pressure gradient is generated to continuously push the gas. The miniature valve device includes a valve plate and a gas outlet plate. After the gas is transferred from the miniature fluid control device to the miniature valve device, the valve opening of the valve plate is correspondingly opened or closed and the gas is transferred in one direction. Consequently, a pressure-collecting operation or a pressure-releasing operation is selectively performed.

FIELD OF THE INVENTION

The present invention relates to a pneumatic device, and moreparticularly to a slim and silent miniature pneumatic device.

BACKGROUND OF THE INVENTION

With the advancement of science and technology, fluid transportationdevices used in many sectors such as pharmaceutical industries, computertechniques, printing industries or energy industries are developedtoward elaboration and miniaturization. The fluid transportation devicesare important components that are used in for example micro pumps, microatomizers, printheads or industrial printers. Therefore, it is importantto provide an improved structure of the fluid transportation device.

For example, in the pharmaceutical industries, pneumatic devices orpneumatic machines use motors or pressure valves to transfer gases.However, due to the volume limitations of the motors and the pressurevalves, the pneumatic devices or the pneumatic machines are bulky involume. In other words, the conventional pneumatic device fails to meetthe miniaturization requirement, can't be installed in or cooperatedwith a portable equipment, and is not portable. Moreover, duringoperations of the motor or the pressure valve, annoying noise is readilygenerated. That is, the conventional pneumatic device is neitherfriendly nor comfortable to the user.

Therefore, there is a need of providing a miniature pneumatic devicewith small, miniature, silent, portable and comfortable benefits inorder to eliminate the above drawbacks.

SUMMARY OF THE INVENTION

The present invention provides a miniature pneumatic device for aportable or wearable equipment or machine. When a piezoelectric ceramicplate is operated at a high frequency, a pressure gradient is generatedin the fluid channels of a miniature fluid control device to facilitatethe gas to flow at a high speed. Moreover, since there is an impedancedifference between the feeding direction and the exiting direction, thegas can be transmitted from the inlet side to the outlet side.Consequently, the miniature pneumatic device is small, slim, portableand silent.

In accordance with an aspect of the present invention, a miniaturepneumatic device is provided. The miniature pneumatic device includes aminiature fluid control device and a miniature valve device. Theminiature fluid control device includes a gas inlet plate, a resonanceplate, a piezoelectric actuator and a gas collecting plate. The gasinlet plate includes at least one inlet, at least one convergencechannel and a central cavity. A convergence chamber is defined by thecentral cavity. After a gas is introduced into the at least oneconvergence channel through the at least one inlet, the gas is guided bythe at least one convergence channel and converged to the convergencechamber. The resonance plate has a central aperture corresponding to theconvergence chamber of the gas inlet plate. The piezoelectric actuatorincludes a suspension plate, an outer frame and a piezoelectric ceramicplate. The suspension plate and the outer frame are connected with eachother through at least one bracket. The piezoelectric ceramic plate isattached on a first surface of the suspension plate. The gas collectingplate includes a first perforation, a second perforation, a firstpressure-releasing chamber, a first outlet chamber and a fiducialsurface. The gas collecting plate further includes a raised structurecorresponding to the first outlet chamber. The raised structure islocated at a level higher than the fiducial surface of the gascollecting plate. The first perforation is in communication with thefirst pressure-releasing chamber. The second perforation is incommunication with the first outlet chamber. The gas inlet plate, theresonance plate, the piezoelectric actuator and the gas collecting plateare stacked on each other sequentially. A gap g0 is formed between theresonance plate and the piezoelectric actuator to define a firstchamber. A difference x between the gap g0 and a vibration displacementd of the piezoelectric actuator is given by a formula: x=g0−d. An outputpressure of gas is generated when x=1˜5 μm. After the gas is fed intothe miniature fluid control device through the at least one inlet of thegas inlet plate, the gas is sequentially converged to the central cavitythrough the at least one convergence channel, transferred through thecentral aperture of the resonance plate, introduced into the firstchamber, transferred downwardly through a vacant space between the atleast one bracket of the piezoelectric actuator, and exited from theminiature fluid control device. The miniature valve device includes avalve plate and a gas outlet plate. The valve plate has a valve opening.A thickness of the valve plate is in a range between 0.1 mm and 0.3 mm.The gas outlet plate includes a pressure-releasing perforation, anoutlet perforation, a second pressure-releasing chamber, a second outletchamber, at least one position-limiting structure and a fiducialsurface. A convex structure is located beside an end of thepressure-releasing perforation. The convex structure is located at alevel higher than the fiducial surface of the gas outlet plate. Theoutlet perforation is in communication with the second outlet chamber.The at least one position-limiting structure is disposed within thesecond pressure-releasing chamber. A thickness of the position-limitingstructure is in a range between 0.2 mm and 0.5 mm. The gas outlet platefurther includes a communication channel between the secondpressure-releasing chamber and the second outlet chamber. The gascollecting plate, the valve plate and the gas outlet plate are combinedtogether. The pressure-releasing perforation of the gas outlet plate isaligned with the first perforation of the gas collecting plate. Thesecond pressure-releasing chamber of the gas outlet plate is alignedwith the first pressure-releasing chamber of the gas collecting plate.The second outlet chamber of the gas outlet plate is aligned with thefirst outlet chamber of the gas collecting plate. The valve plate isarranged between the gas collecting plate and the gas outlet plate forblocking communication between the first pressure-releasing chamber andthe second pressure-releasing chamber. The valve opening of the valveplate is arranged between the second perforation and the outletperforation. After the gas is downwardly transferred from the miniaturefluid control device to the miniature valve device, the gas isintroduced into the first pressure-releasing chamber and the firstoutlet chamber through the first perforation and the second perforation,and the valve plate is quickly contacted with the convex structure ofthe gas outlet plate to provide a pre-force to tightly close thepressure-releasing perforation, and the gas within the first outletchamber is further transferred to the outlet perforation through thevalve opening of the valve plate. Consequently, a pressure-collectingoperation is performed. While a pressure-releasing operation isperformed, the gas is transferred from the outlet perforation to thesecond outlet chamber to move the valve plate, the valve opening of thevalve plate is contacted with and closed by the gas collecting plate,the at least one position-limiting structure assists in supporting thevalve plate to avoid collapse of the valve plate, the gas is transferredfrom the second outlet chamber to the second pressure-releasing chamberthrough the communication channel, the valve plate corresponding to thesecond pressure-releasing chamber is moved, and the gas is exited fromthe pressure-releasing perforation.

In accordance with another aspect of the present invention, a miniaturepneumatic device is provided. The miniature pneumatic device includes aminiature fluid control device and a miniature valve device. Theminiature fluid control device includes a gas inlet plate, a resonanceplate, a piezoelectric actuator and a gas collecting plate. The gascollecting plate includes a first perforation, a second perforation, afirst pressure-releasing chamber and a first outlet chamber. The gasinlet plate, the resonance plate, the piezoelectric actuator and the gascollecting plate are stacked on each other sequentially. A gap g0 isformed between the resonance plate and the piezoelectric actuator todefine a first chamber. A gas-collecting chamber is formed between thepiezoelectric actuator and the gas collecting plate. A difference xbetween the gap g0 and a vibration displacement d of the piezoelectricactuator is given by a formula: x=g0−d. An output pressure of gas isgenerated when x=1˜5 μm. After the gas is fed into the miniature fluidcontrol device through the gas inlet plate, the gas is transferredthrough the resonance plate, introduced into the first chamber, andtransferred downwardly to the gas-collecting chamber. The miniaturevalve device includes a valve plate and a gas outlet plate. The valveplate has a valve opening. The gas outlet plate includes apressure-releasing perforation, an outlet perforation, a secondpressure-releasing chamber and a second outlet chamber. The gascollecting plate, the valve plate and the gas outlet plate are combinedtogether. After the gas is downwardly transferred from thegas-collecting chamber to the miniature valve device, the gas istransferred through the first perforation, the second perforation, thefirst pressure-releasing chamber, the first outlet chamber, the secondpressure-releasing chamber, the second outlet chamber, thepressure-releasing perforation and the outlet perforation. The gas istransferred in one direction, and the valve opening of the valve plateis correspondingly opened or closed, so that a pressure-collectingoperation or a pressure-releasing operation is selectively performed.

In accordance with a further aspect of the present invention, aminiature pneumatic device is provided. The miniature pneumatic deviceincludes a miniature fluid control device and a miniature valve device.The miniature fluid control device includes a gas inlet plate, aresonance plate, a piezoelectric actuator and a gas collecting plate.The gas inlet plate, the resonance plate, the piezoelectric actuator andthe gas collecting plate are stacked on each other sequentially. A gapg0 is formed between the resonance plate and the piezoelectric actuatorto define a first chamber. A difference x between the gap g0 and avibration displacement d of the piezoelectric actuator is given by aformula: x=g0−d. An output pressure of gas is generated when x=1˜5 μm.After the gas is fed into the miniature fluid control device through thegas inlet plate, the gas is transferred through the resonance plate,introduced into the first chamber, and exited from the miniature fluidcontrol device. The miniature valve device includes a valve plate havinga valve opening and a gas outlet plate. The valve plate has a valveopening. The gas collecting plate, the valve plate and the gas outletplate are combined together. After the gas is transferred from theminiature fluid control device to the miniature valve device, apressure-collecting operation or a pressure-releasing operation isselectively performed.

The above contents of the present invention will become more readilyapparent to those ordinarily skilled in the art after reviewing thefollowing detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic exploded view illustrating a miniature pneumaticdevice according to an embodiment of the present invention and takenalong a first viewpoint;

FIG. 1B is a schematic assembled view illustrating the miniaturepneumatic device of FIG. 1A;

FIG. 2A is a schematic exploded view illustrating the miniaturepneumatic device according to the embodiment of the present inventionand taken along a second viewpoint;

FIG. 2B is a schematic assembled view illustrating the miniaturepneumatic device of FIG. 2A;

FIG. 3A is a schematic perspective view illustrating the piezoelectricactuator of the miniature pneumatic device of FIG. 1A and taken alongthe front side;

FIG. 3B is a schematic perspective view illustrating the piezoelectricactuator of the miniature pneumatic device of FIG. 1A and taken alongthe rear side;

FIG. 3C is a schematic cross-sectional view illustrating thepiezoelectric actuator of the miniature pneumatic device of FIG. 1A;

FIGS. 4A to 4C schematically illustrate various exemplary piezoelectricactuator used in the miniature pneumatic device of the presentinvention;

FIGS. 5A to 5E schematically illustrate the actions of the miniaturefluid control device of the miniature pneumatic device of FIG. 1A;

FIG. 6A schematically illustrate a gas-collecting operation of the gascollecting plate and miniature valve device of the miniature pneumaticdevice of FIG. 1A;

FIG. 6B schematically illustrate a gas-releasing operation of the gascollecting plate and miniature valve device of the miniature pneumaticdevice of FIG. 1A;

FIGS. 7A to 7E schematically illustrate a gas-collecting operation ofthe miniature pneumatic device of FIG. 1A; and

FIG. 8 schematically illustrate the gas-releasing actions or thepressure-reducing actions of the miniature pneumatic device of FIG. 1A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this invention arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

The present invention provides a miniature pneumatic device. Theminiature pneumatic device may be used in many sectors such aspharmaceutical industries, energy industries, computer techniques orprinting industries for transporting gases.

Please refer to FIGS. 1A, 1B, 2A, 2B and 7A to 7E. FIG. 1A is aschematic exploded view illustrating a miniature pneumatic deviceaccording to an embodiment of the present invention and taken along afirst viewpoint. FIG. 1B is a schematic assembled view illustrating theminiature pneumatic device of FIG. 1A. FIG. 2A is a schematic explodedview illustrating the miniature pneumatic device according to theembodiment of the present invention and taken along a second viewpoint.FIG. 2B is a schematic assembled view illustrating the miniaturepneumatic device of FIG. 2A. FIGS. 7A to 7E schematically illustrate agas-collecting operation of the miniature pneumatic device of FIG. 1A.

As shown in FIGS. 1A and 2A, the miniature pneumatic device 1 comprisesa miniature fluid control device 1A and a miniature valve device 1B. Inthis embodiment, the miniature fluid control device 1A comprises ahousing 1 a, a piezoelectric actuator 13, a first insulation plate 141,a conducting plate 15 and a second insulation plate 142. The housing 1 acomprises a gas collecting plate 16 and a base 10. The base 10 comprisesa gas inlet plate 11 and a resonance plate 12. The piezoelectricactuator 13 is aligned with the resonance plate 12. The gas inlet plate11, the resonance plate 12, the piezoelectric actuator 13, the firstinsulation plate 141, the conducting plate 15, the second insulationplate 142 and the gas collecting plate 16 are stacked on each othersequentially. Moreover, the piezoelectric actuator 13 comprises asuspension plate 130, an outer frame 131, at least one bracket 132 and apiezoelectric ceramic plate 133. In this embodiment, the miniature valvedevice 1B comprises a valve plate 17 and a gas outlet plate 18.

As shown in FIG. 1A, the gas collecting plate 16 comprises a bottomplate and a sidewall 168. The sidewall 168 is protruded from the edgesof the bottom plate. The length of the gas collecting plate 16 is in therange between 9 mm and 17 mm. The width of the gas collecting plate 16is in the range between 9 mm and 17 mm. Preferably, the length/widthratio of the gas collecting plate 16 is in the range between 0.53 and1.88. Moreover, an accommodation space 16 a is defined by the bottomplate and the sidewall 168 collaboratively. The piezoelectric actuator13 is disposed within the accommodation space 16 a. After the miniaturepneumatic device 1 is assembled, the resulting structure of theminiature pneumatic device taken from the front side is shown in FIG. 1Band FIGS. 7A to 7E. The miniature fluid control device 1A and theminiature valve device 1B are combined together. That is, the valveplate 17 and the gas outlet plate 18 of the miniature valve device 1Bare stacked on each other and positioned on the gas collecting plate 16of the miniature fluid control device 1A. The gas outlet plate 18comprises a pressure-releasing perforation 181 and an outlet structure19. The outlet structure 19 is in communication with an equipment (notshown). When the gas in the miniature valve device 1B releases from thepressure-releasing perforation 181, the pressure-releasing purpose isachieved.

After the miniature fluid control device 1A and the miniature valvedevice 1B are combined together, the miniature pneumatic device 1 isassembled. Consequently, a gas is fed into the miniature fluid controldevice 1A through at least one inlet 110 of the gas inlet plate 11. Inresponse to the actions of the piezoelectric actuator 13, the gas istransferred downwardly through plural pressure chambers (not shown).Then, the gas is transferred through the miniature valve device 1B inone direction. The pressure of the gas is accumulated in an equipment(not shown) that is in communication with the outlet structure 19 of theminiature valve device 1B. For releasing the pressure, the output gasamount of the miniature fluid control device 1A is exited from thepressure-releasing perforation 181 of the gas outlet plate 18 of theminiature valve device 1B.

Please refer to FIGS. 1A and 2A again. The gas inlet plate 11 of theminiature fluid control device 1A comprises a first surface 11 b, asecond surface 11 a and the at least one inlet 110. In this embodiment,the gas inlet plate 11 comprises four inlets 110. The inlets 110 runthrough the first surface 11 b and the second surface 11 a of the gasinlet plate 11. In response to the action of the atmospheric pressure,the gas can be introduced into the miniature fluid control device 1Athrough the at least one inlet 110. As shown in FIG. 2A, at least oneconvergence channel 112 is formed in the first surface 11 b of the gasinlet plate 11. The at least one convergence channel 112 is incommunication with the at least one inlet 110 in the second surface 11 aof the gas inlet plate 11. The number of the at least one convergencechannel 112 is identical to the number of the at least one inlet 110. Inthis embodiment, the gas inlet plate 11 comprises four convergencechannels 112. It is noted that the number of the at least oneconvergence channel 112 and the number of the at least one inlet 110 maybe varied according to the practical requirements. Moreover, a centralcavity 111 is formed in the first surface 11 b of the gas inlet plate 11and located at a central convergence area of the four convergencechannels 112. The central cavity 111 is in communication with the atleast one convergence channel 112. After the gas is introduced into theat least one convergence channel 112 through the at least one inlet 110,the gas is guided to the central cavity 111. In this embodiment, the atleast one inlet 110, the at least one convergence channel 112 and thecentral cavity 111 of the gas inlet plate 11 are integrally formed. Thecentral cavity 111 is a convergence chamber for temporarily storing thegas.

Preferably but not exclusively, the gas inlet plate 11 is made ofstainless steel. The thickness of the gas inlet plate 11 is in the rangebetween 0.4 mm and 0.6 mm, and preferably 0.5 mm. Moreover, the depth ofthe convergence chamber defined by the central cavity 111 and the depthof the at least one convergence channel 112 are equal. For example, thedepth of the convergence chamber and the depth of the at least oneconvergence channel 112 are in the range between 0.2 mm and 0.3 mm.Preferably but not exclusively, the resonance plate 12 is made offlexible material. The resonance plate 12 comprises a central aperture120 corresponding to the central cavity 111 of the gas inlet plate 11.Consequently, the gas can be transferred downwardly through the centralaperture 120. Preferably but not exclusively, the resonance plate 12 ismade of copper. The thickness of the resonance plate 12 is in the rangebetween 0.03 mm and 0.08 mm, and preferably 0.05 mm.

FIG. 3A is a schematic perspective view illustrating the piezoelectricactuator of the miniature pneumatic device of FIG. 1A and taken alongthe front side. FIG. 3B is a schematic perspective view illustrating thepiezoelectric actuator of the miniature pneumatic device of FIG. 1A andtaken along the rear side. FIG. 3C is a schematic cross-sectional viewillustrating the piezoelectric actuator of the miniature pneumaticdevice of FIG. 1A. As shown in FIGS. 3A, 3B and 3C, the piezoelectricactuator 13 comprises the suspension plate 130, the outer frame 131, theat least one bracket 132, and the piezoelectric ceramic plate 133. Thepiezoelectric ceramic plate 133 is attached on a first surface 130 b ofthe suspension plate 130. The piezoelectric ceramic plate 133 issubjected to a curvy vibration in response to an applied voltage. Thesuspension plate 130 comprises a middle portion 130 d and a peripheryportion 130 e. When the piezoelectric ceramic plate 133 is subjected tothe curvy vibration, the suspension plate 130 is subjected to the curvyvibration from the middle portion 130 d to the periphery portion 130 e.The at least one bracket 132 is arranged between the suspension plate130 and the outer frame 131. That is, the at least one bracket 132 isconnected between the suspension plate 130 and the outer frame 131. Thetwo ends of the bracket 132 are connected with the outer frame 131 andthe suspension plate 130, respectively. Consequently, the bracket 131can elastically support the suspension plate 130. Moreover, at least onevacant space 135 is formed between the bracket 132, the suspension plate130 and the outer frame 131 for allowing the gas to go through. The typeof the suspension plate 130 and the outer frame 131 and the type and thenumber of the at least one bracket 132 may be varied according to thepractical requirements. Moreover, a conducting pin 134 is protrudedoutwardly from the outer frame 131 so as to be electrically connectedwith an external circuit (not shown).

In this embodiment, the suspension plate 130 is a stepped structure.That is, the suspension plate 130 comprises a bulge 130 c. The bulge 130c is formed on a second surface 130 a of the suspension plate 130. Forexample, the bulge 130 c is a circular convex structure. The thicknessof the bulge 130 c is in the range between 0.02 mm and 0.08 mm, andpreferably 0.03 mm. Preferably but not exclusively, the diameter of thebulge 130 c is 0.55 times the short side length of the suspension plate130. As shown in FIGS. 3A and 3C, a top surface of the bulge 130 c ofthe suspension plate 130 is coplanar with a second surface 131 a of theouter frame 131, and the second surface 130 a of the suspension plate130 is coplanar with a second surface 132 a of the bracket 132.Moreover, the bulge 130 c of the suspension plate 130 (or the secondsurface 131 a of the outer frame 131) has a specified thickness withrespect to the second surface 130 a of the suspension plate 130 (or thesecond surface 132 a of the bracket 132). As shown in FIGS. 3B and 3C, afirst surface 130 b of the suspension plate 130, a first surface 131 bof the outer frame 131 and a first surface 132 b of the bracket 132 arecoplanar with each other. The piezoelectric ceramic plate 133 isattached on the first surface 130 b of the suspension plate 130. In someother embodiments, the suspension plate 130 is a square plate structurewith two flat surfaces. That is, the structure of the suspension plate130 may be varied according to the practical requirements. In thisembodiment, the suspension plate 130, the at least bracket 132 and theouter frame 131 are integrally formed and produced by using a metalplate (e.g., a stainless steel plate). The thickness of the suspensionplate 130 is in the range between 0.1 mm and 0.4 mm, and preferably 0.27mm. The length of the suspension plate 130 is in the range between 7.5mm and 12 mm, and preferably in the range between 7.5 mm and 8.5 mm. Thewidth of the suspension plate 130 is in the range between 7.5 mm and 12mm, and preferably in the range between 7.5 mm and 8.5 mm. The thicknessof the outer frame 131 is in the range between 0.2 mm and 0.4 mm, andpreferably 0.3 mm.

The thickness of the piezoelectric ceramic plate 133 is in the rangebetween 0.05 mm and 0.3 mm, and preferably 0.10 mm. The length of thepiezoelectric ceramic plate 133 is not larger than the length of thesuspension plate 130. The length of the piezoelectric ceramic plate 133is in the range between 7.5 mm and 12 mm, and preferably in the rangebetween 7.5 mm and 8.5 mm. The width of the piezoelectric ceramic plate133 is in the range between 7.5 mm and 12 mm, and preferably in therange between 7.5 mm and 8.5 mm. Moreover, the length/width ratio of thepiezoelectric ceramic plate 133 is in the range between 0.625 and 1.6.In some embodiments, the length of the piezoelectric ceramic plate 133is smaller than the length of the suspension plate 130. Similarly, thepiezoelectric ceramic plate 133 is a square plate structurecorresponding to the suspension plate 130.

Preferably, the suspension plate 130 of the piezoelectric actuator 13used in the miniature pneumatic device 1 of the present invention is asquare suspension plate. In comparison with the circular suspensionplate (e.g., the circular suspension plate j0 as shown in FIG. 4A), thesquare suspension plate is more power-saving. The comparison between theconsumed power and the operating frequency for the suspension plates ofdifferent types and sizes is shown in Table 1.

TABLE 1 Type and size of Operating Consumed suspension plate frequencypower Square (side length: 10 mm) 18 kHz 1.1 W Circular (diameter: 10mm) 28 kHz 1.5 W Square (side length: 9 mm) 22 kHz 1.3 W Circular(diameter: 9 mm) 34 kHz   2 W Square (side length: 8 mm) 27 kHz 1.5 WCircular (diameter: 8 mm) 42 kHz 2.5 W

From the results of Table 1, it is found that the piezoelectric actuatorwith the square suspension plate (8 mm˜10 mm) is more power-saving thanthe piezoelectric actuator with the circular suspension plate (8 mm˜10mm). That is, the piezoelectric actuator with the square suspensionplate consumes less power. Generally, the consumed power of thecapacitive load at the resonance frequency is positively related to theresonance frequency. Since the resonance frequency of the squaresuspension plate is obviously lower than that of the circular squaresuspension plate, the consumed power of the square suspension plate islower. Since the square suspension plate is more power-saving than thecircular suspension plate, the square suspension plate is suitably usedin the wearable device. The fact that the square suspension plate ismore power-saving than the circular suspension plate is realizedaccording to the results of experiments rather than theoreticalmathematic formulae.

FIGS. 4A, 4B and 4C schematically illustrate various exemplarypiezoelectric actuator used in the miniature pneumatic device of thepresent invention. As shown in the drawings, the suspension plate 130,the outer frame 131 and the at least one bracket 132 of thepiezoelectric actuator 13 have various types.

FIG. 4A schematically illustrates the types (a)˜(l) of the piezoelectricactuator. In the type (a), the outer frame a1 and the suspension platea0 are square, the outer frame a1 and the suspension plate a0 areconnected with each other through eight brackets a2, and a vacant spacea3 is formed between the brackets a2, the suspension plate a0 and theouter frame a1 for allowing the gas to go through. In the type (i), theouter frame i1 and the suspension plate i0 are also square, but theouter frame i1 and the suspension plate i0 are connected with each otherthrough two brackets i2. In addition, the outer frame and the suspensionplate in each of the types (b)˜(h) are also square. In each of the types(j)˜(l), the suspension plate is circular, and the outer frame has asquare with arc-shaped corners. For example, in the type (j), thesuspension plate j0 is circular, and the outer frame has a square witharc-shaped corners.

FIG. 4B schematically illustrates the types (m)˜(r) of the piezoelectricactuator. In these types (m)˜(r), the suspension plate 130 and the outerframe 131 are square. In the type (m), the outer frame m1 and thesuspension plate m0 are square, the outer frame m1 and the suspensionplate m0 are connected with each other through four brackets m2, and avacant space m3 is formed between the brackets m2, the suspension platem0 and the outer frame m1 for allowing the gas to go through. Thebracket m2 between the outer frame m1 and the suspension plate m0 is aconnecting part. The bracket m2 has two ends m2′ and m2″. The end m2′ ofthe bracket m2 is connected with the outer frame m1. The end m2″ of thebracket m2 is connected with the suspension plate m0. The two ends m2′and m2″ are opposed to each other and arranged along the same horizontalline. In the type (n), the outer frame n1 and the suspension plate m0are square, the outer frame n1 and the suspension plate n0 are connectedwith each other through four brackets n2, and a vacant space n3 isformed between the brackets n2, the suspension plate n0 and the outerframe n1 for allowing the gas to go through. The bracket n2 between theouter frame n1 and the suspension plate n0 is a connecting part. Thebracket n2 has two ends n2′ and n2″. The end n2′ of the bracket n2 isconnected with the outer frame n1. The end n2″ of the bracket n2 isconnected with the suspension plate n0. The two ends n2′ and n2″ are notarranged along the same horizontal line. For example, the two ends n2′and n2″ are inclined at 0˜45 degrees with respect to the horizontalline, and the two ends n2′ and n2″ are interlaced. In the type (o), theouter frame o1 and the suspension plate o0 are square, the outer frameo1 and the suspension plate o0 are connected with each other throughfour brackets o2, and a vacant space o3 is formed between the bracketso2, the suspension plate o0 and the outer frame o1 for allowing the gasto go through. The bracket o2 between the outer frame o1 and thesuspension plate o0 is a connecting part. The bracket o2 has two endso2′ and o2″. The end o2′ of the bracket o2 is connected with the outerframe o1. The end o2″ of the bracket o2 is connected with the suspensionplate o0. The two ends o2′ and o2″ are opposed to each other andarranged along the same horizontal line. In comparison with the abovetypes, the profile of the bracket o2 is distinguished.

In the type (p), the outer frame p1 and the suspension plate p0 aresquare, the outer frame p1 and the suspension plate p0 are connectedwith each other through four brackets p2, and a vacant space p3 isformed between the brackets p2, the suspension plate p0 and the outerframe p1 for allowing the gas to go through. The bracket p2 between theouter frame p1 and the suspension plate p0 comprises a first connectingpart p20, an intermediate part p21 and a second connecting part p22. Theintermediate part p21 is formed in the vacant space p3 and in parallelwith the outer frame p1 and the suspension plate p0. The firstconnecting part p20 is arranged between the intermediate part p21 andthe suspension plate p0. The second connecting part p22 is arrangedbetween the intermediate part p21 and the outer frame p1. The firstconnecting part p20 and the second connecting part p22 are opposed toeach other and arranged along the same horizontal line.

In the type (q), the outer frame q1, the suspension plate q0, thebracket q2 and the vacant space q3 are similar to those of the type (m)and the type (o). However, the structure of the bracket q2 isdistinguished. The suspension plate q0 is square. Each side of thesuspension plate q0 is connected with the corresponding side of theouter frame q1 through two connecting parts q2. The two ends q2′ and q2″of each connecting part q2 are opposed to each other and arranged alongthe same horizontal line. In the type (r), the outer frame r1, thesuspension plate r0, the bracket r2 and the vacant space r3 are similarto those of the above embodiments. However, the bracket r2 is a V-shapedconnecting part. That is, the bracket r2 is connected with the outerframe r1 and the suspension plate r0 at an inclined angle 0˜45 degrees.An end r2″ of the bracket r2 is connected with the suspension plate r0,and two ends r2′ of the bracket r2 is connected with the outer frame r1.That is, the ends b2′ and b2″ are not arranged along the same horizontalline.

FIG. 4C schematically illustrates the types (s)˜(x) of the piezoelectricactuator. The structures of the types (s)˜(x) are similar to those ofthe types (m)˜(r), respectively. However, in the types (s)˜(x), thesuspension plate 130 of the piezoelectric actuator 13 has a bulge 130 c.The bulges 130 c in the types (s)˜(x) are indicated as s4, t4, u4, v4,w4 and x4, respectively. The suspension plate 130 is square, and thusthe power-saving efficacy is achieved. As mentioned above, the steppedstructure comprising the bulge and the square plate structure with twoflat surfaces are suitably used as the suspension plates of the presentinvention. Moreover, the number of the brackets 132 between the outerframe 131 and the suspension plate 130 may be varied according to thepractical requirements. Moreover, the suspension plate 130, the outerframe 131 and the at least one bracket 132 are integrally formed witheach other and produced by a conventional machining process, aphotolithography and etching process, a laser machining process, anelectroforming process, an electric discharge machining process and soon.

Please refer to FIGS. 1A and 2A again. The miniature fluid controldevice 1A further comprises the first insulation plate 141, theconducting plate 15 and the second insulation plate 142. The firstinsulation plate 141, the conducting plate 15 and the second insulationplate 142 are stacked on each other sequentially and located under thepiezoelectric actuator 13. The profiles of the first insulation plate141, the conducting plate 15 and the second insulation plate 142substantially match the profile of the outer frame 131 of thepiezoelectric actuator 13. The first insulation plate 141 and the secondinsulation plate 142 are made of an insulating material (e.g. a plasticmaterial) for providing insulating efficacy. The conducting plate 15 ismade of an electrically conductive material (e.g. a metallic material)for providing electrically conducting efficacy. Moreover, the conductingplate 15 has a conducting pin 151 so as to be electrically connectedwith an external circuit (not shown).

FIGS. 5A to 5E schematically illustrate the actions of the miniaturefluid control device of the miniature pneumatic device of FIG. 1A. Asshown in FIG. 5A, the gas inlet plate 11, the resonance plate 12, thepiezoelectric actuator 13, the first insulation plate 141, theconducting plate 15 and the second insulation plate 142 of the miniaturefluid control device 1A are stacked on each other sequentially.Moreover, there is a gap g0 between the resonance plate 12 and the outerframe 131 of the piezoelectric actuator 13. In this embodiment, a filler(e.g. a conductive adhesive) is inserted into the gap g0. Consequently,the depth of the gap g0 between the resonance plate 12 and the bulge 130c of the suspension plate 130 can be maintained to guide the gas to flowmore quickly. Moreover, due to the proper distance between the resonanceplate 12 and the bulge 130 c of the suspension plate 130, the contactinterference is reduced and the generated noise is largely reduced.

Please refer to FIGS. 5A to 5E again. After the gas inlet plate 11, theresonance plate 12 and the piezoelectric actuator 13 are combinedtogether, a convergence chamber for converging the gas is defined by thecentral aperture 120 of the resonance plate 12 and the gas inlet plate11 collaboratively, and a first chamber 121 is formed between theresonance plate 12 and the piezoelectric actuator 13 for temporarilystoring the gas. Through the central aperture 120 of the resonance plate12, the first chamber 121 is in communication with the central cavity111 that is formed in the first surface 11 b of the gas inlet plate 11.The peripheral regions of the first chamber 121 are in communicationwith the underlying miniature valve device 1B through the vacant space135 of the piezoelectric actuator 13.

When the miniature fluid control device 1A of the miniature pneumaticdevice 1 is enabled, the piezoelectric actuator 13 is actuated by anapplied voltage. Consequently, the piezoelectric actuator 13 is vibratedalong a vertical direction in a reciprocating manner by using thebracket 132 as a fulcrum. The resonance plate 12 is light and thin.Please refer to FIG. 5B. When the piezoelectric actuator 13 is vibrateddownwardly in response to the applied voltage, the resonance plate 12 isvibrated along the vertical direction in the reciprocating mannerbecause of the resonance of the piezoelectric actuator 13. Moreespecially, the portion of the resonance plate 12 corresponding to thecentral cavity 111 of the gas inlet plate 11 is also subjected to acurvy deformation. Hereinafter, the region of the resonance plate 12corresponding to the central cavity 111 of the gas inlet plate 11 isalso referred as a movable part 12 a of the resonance plate 12. When thepiezoelectric actuator 13 is vibrated downwardly, the movable part 12 aof the resonance plate 12 is subjected to the curvy deformation becausethe movable part 12 a of the resonance plate 12 is pushed by the gas andvibrated in response to the piezoelectric actuator 13. After the gas isfed into the at least one inlet 110 of the gas inlet plate 11, the gasis transferred to the central cavity 111 of the gas inlet plate 11through the at least one convergence channel 112. Then, the gas istransferred through the central aperture 120 of the resonance plate 12,and introduced downwardly into the first chamber 121. As thepiezoelectric actuator 13 is actuated, the resonance of the resonanceplate 12 occurs. Consequently, the movable part 12 of the resonanceplate 12 is also vibrated along the vertical direction in thereciprocating manner.

As shown in FIG. 5C, the resonance plate 12 is vibrated downwardly andcontacted with the bulge 130 c of the suspension plate 130 of thepiezoelectric actuator 13. The region of the resonance plate 12excluding the movable part 12 a is also referred as a fixed part 12 b.Meanwhile, the gap between the suspension plate 130 and the fixed part12 b of the resonance plate 12 is not reduced. Due to the deformation ofthe resonance plate 12, the volume of the first chamber 121 is shrunkenand a middle communication space of the first chamber 121 is closed.Under this circumstance, the gas is pushed toward peripheral regions ofthe first chamber 121. Consequently, the gas is transferred downwardlythrough the vacant space 135 of the piezoelectric actuator 13.

As shown in FIG. 5D, the resonance plate 12 is returned to its originalposition after the movable part 12 a of the resonance plate 12 issubjected to the curvy deformation. Then, the piezoelectric actuator 13is vibrated upwardly in response to the applied voltage. Consequently,the volume of the first chamber 121 is also shrunken. Since thepiezoelectric actuator 13 is ascended at a vibration displacement d, thegas is continuously pushed toward peripheral regions of the firstchamber 121. Meanwhile, the gas is continuously fed into the at leastone inlet 110 of the gas inlet plate 11, and transferred to the centralcavity 111.

Then, as shown in FIG. 5E, the resonance plate 12 is moved upwardlybecause the piezoelectric actuator 13 is vibrated upwardly. That is, themovable part 12 a of the resonance plate 12 is moved upwardly. Underthis circumstance, the gas in the central cavity 111 is transferred tothe first chamber 121 through the central aperture 120 of the resonanceplate 12, then the gas is transferred downwardly through the vacantspace 135 of the piezoelectric actuator 13, and finally the gas isexited from the miniature fluid control device 1A.

From the above discussions, when the resonance plate 12 is vibratedalong the vertical direction in the reciprocating manner, the gap g0between the resonance plate 12 and the piezoelectric actuator 13 ishelpful to increase the amplitude of the resonance plate 12. That is,due to the gap g0 between the resonance plate 12 and the piezoelectricactuator 13, the amplitude of the resonance plate 12 is increased whenthe resonance occurs. The difference x between the gap g0 and thevibration displacement d of the piezoelectric actuator 13 is given by aformula: x=g0−d. A series of tests about the maximum output pressure ofthe miniature pneumatic device 1 corresponding to different values of xare performed. In case that x≤0 μm, the miniature pneumatic device 1generates noise. In case that x=1˜5 μm, the maximum output pressure ofthe miniature pneumatic device 1 is 350 mmHg. In case that x=5˜10 μm,the maximum output pressure of the miniature pneumatic device 1 is 250mmHg. In case that x=10˜15 μm, the maximum output pressure of theminiature pneumatic device 1 is 150 mmHg. The relationships between thedifference x and the maximum output pressure are listed in Table 2. Thevalues of Table 2 are obtained when the operating frequency is in therange between 17 kHz and 20 kHz and the operating voltage is in therange between ±10V and ±20V. Consequently, a pressure gradient isgenerated in the fluid channels of the miniature fluid control device 1Ato facilitate the gas to flow at a high speed. Moreover, since there isan impedance difference between the feeding direction and the exitingdirection, the gas can be transmitted from the inlet side to the outletside. Moreover, even if the outlet side has a gas pressure, theminiature fluid control device 1A still has the capability of pushingout the gas while achieving the silent efficacy.

TABLE 2 Maximum output Test X pressure 1 x = 1~5 μm 350 mmHg 2 x = 5~10μm 250 mmHg 3 x = 10~15 μm 150 mmHg

In some embodiments, the vibration frequency of the resonance plate 12along the vertical direction in the reciprocating manner is identical tothe vibration frequency of the piezoelectric actuator 13. That is, theresonance plate 12 and the piezoelectric actuator 13 are synchronouslyvibrated along the upward direction or the downward direction. It isnoted that numerous modifications and alterations of the actions of theminiature fluid control device 1A may be made while retaining theteachings of the invention.

Please refer to FIGS. 1A, 2A, 6A and 6B. FIG. 6A schematicallyillustrate a gas-collecting operation of the gas collecting plate andminiature valve device of the miniature pneumatic device of FIG. 1A.FIG. 6B schematically illustrate a gas-releasing operation of the gascollecting plate and miniature valve device of the miniature pneumaticdevice of FIG. 1A. As shown in FIGS. 1A and 6A, the valve plate 17 andthe gas outlet plate 18 of the miniature valve device 1B are stacked oneach other sequentially. Moreover, the miniature valve device 1B and thegas collecting plate 16 of the miniature fluid control device 1Acooperate with each other.

The gas collecting plate 16 comprises a first surface 160 and a secondsurface 161 (also referred as a fiducial surface). The first surface 160of the gas collecting plate 16 is concaved to define a gas-collectingchamber 162. The piezoelectric actuator 13 is accommodated within thegas-collecting chamber 162. The gas that is transferred downwardly bythe miniature fluid control device 1A is temporarily accumulated in thegas-collecting chamber 162. The gas collecting plate 16 comprises afirst perforation 163 and a second perforation 164. A first end of thefirst perforation 163 and a first end of the second perforation 164 arein communication with the gas-collecting chamber 162. A second end ofthe first perforation 163 and a second end of the second perforation 164are in communication with a first pressure-releasing chamber 165 and afirst outlet chamber 166, which are formed in the second surface 161 ofthe gas collecting plate 16. Moreover, the gas collecting plate 16 has araised structure 167 corresponding to the first outlet chamber 166. Forexample, the raised structure 167 includes but is not limited to acylindrical post. The raised structure 167 is located at a level higherthan the second surface 161 of the gas collecting plate 16. Moreover, athickness of the raised structure 167 is in a range between 0.3 mm and0.55 mm, and preferably 0.4 mm.

The gas outlet plate 18 comprises a pressure-releasing perforation 181,an outlet perforation 182, a first surface 180 (also referred as afiducial surface) and a second surface 187. The pressure-releasingperforation 181 and the outlet perforation 182 run through the firstsurface 180 and the second surface 187. The first surface 180 of the gasoutlet plate 18 is concaved to define a second pressure-releasingchamber 183 and a second outlet chamber 184. The pressure-releasingperforation 181 is located at a center of the second pressure-releasingchamber 183. Moreover, the gas outlet plate 18 further comprises acommunication channel 185 between the second pressure-releasing chamber183 and the second outlet chamber 184 for allowing the gas to gothrough. A first end of the outlet perforation 182 is in communicationwith the second outlet chamber 184. A second end of the outletperforation 182 is in communication with an outlet structure 19. Theoutlet structure 19 is in connected with an equipment (not shown). Theequipment is for example but not limited to a gas-pressure drivingequipment.

The valve plate 17 comprises a valve opening 170 and plural positioningopenings 171 (see FIG. 1A). The thickness of the valve plate 17 is inthe range between 0.1 mm and 0.3 mm, and preferably 0.2 mm.

After the gas collecting plate 16, the valve plate 17 and the gas outletplate 18 are combined together, the pressure-releasing perforation 181of the gas outlet plate 18 is aligned with the first perforation 163 ofthe gas collecting plate 16, the second pressure-releasing chamber 183of the gas outlet plate 18 is aligned with the first pressure-releasingchamber 165 of the gas collecting plate 16, and the second outletchamber 184 of the gas outlet plate 18 is aligned with the first outletchamber 166 of the gas collecting plate 16. The valve plate 17 isarranged between the gas collecting plate 16 and the gas outlet plate 18for blocking the communication between the first pressure-releasingchamber 165 and the second pressure-releasing chamber 183. The valveopening 170 of the valve plate 17 is arranged between the secondperforation 164 and the outlet perforation 182. Moreover, the valveopening 170 of the valve plate 17 is aligned with the raised structure167 corresponding to the first outlet chamber 166 of the gas collectingplate 16. Due to the arrangement of the single valve opening 170, thegas is transferred through the miniature valve device 1B in onedirection in response to the pressure difference.

In this embodiment, the gas outlet plate 18 has the convex structure 181a beside a first end of the pressure-releasing perforation 181.Preferably but not exclusively, the convex structure 181 a is acylindrical post. The thickness of the convex structure 181 a is in therange between 0.3 mm and 0.55 mm, and preferably 0.4 mm. The top surfaceof the convex structure 181 a is located at a level higher than thefirst surface 180 of the gas outlet plate 18. Consequently, thepressure-releasing perforation 181 can be quickly contacted with andclosed by the valve plate 17. Moreover, the convex structure 181 a canprovide a pre-force to achieve a good sealing effect. In thisembodiment, the gas outlet plate 18 further comprises aposition-limiting structure 188. The thickness of the position-limitingstructure 188 is 0.32 mm. The position-limiting structure 188 isdisposed within the second pressure-releasing chamber 183. Preferablybut not exclusively, the position-limiting structure 188 is aring-shaped structure. While the gas-collecting operation of theminiature valve device 1B is performed, the position-limiting structure188 can assist in supporting the valve plate 17 and avoid collapse ofthe valve plate 17. Consequently, the valve plate 17 can be opened orclosed more quickly.

Hereinafter, the gas-collecting operation of the miniature valve device1B will be illustrated with reference to FIG. 6A. In case that the gasfrom the miniature fluid control device 1A is transferred downwardly tothe miniature valve device 1B or the ambient air pressure is higher thanthe inner pressure of the equipment which is in communication with theoutlet structure 19, the gas will be transferred from the miniaturefluid control device 1A to the gas-collecting chamber 162 of the gascollecting plate 16. Then, the gas is transferred downwardly to thefirst pressure-releasing chamber 165 and the first outlet chamber 166through the first perforation 163 and the second perforation 164. Inresponse to the downward gas, the flexible valve plate 17 is subjectedto a downward curvy deformation. Consequently, the volume of the firstpressure-releasing chamber 165 is expanded, and the valve plate 17 is inclose contact with the first end of the pressure-releasing perforation181 corresponding to the first perforation 163. Under this circumstance,the pressure-releasing perforation 181 of the gas outlet plate 18 isclosed, and thus the gas within the second pressure-releasing chamber183 is not leaked out from the pressure-releasing perforation 181. Inthis embodiment, the gas outlet plate 18 has the convex structure 181 abeside of the first end of the pressure-releasing perforation 181. Dueto the arrangement of the convex structure 181 a, the pressure-releasingperforation 181 can be quickly closed by the valve plate 17. Moreover,the convex structure 181 a can provide a pre-force to achieve a goodsealing effect. The position-limiting structure 188 is arranged aroundthe pressure-releasing perforation 181 to assist in supporting the valveplate 17 and avoid collapse of the valve plate 17. On the other hand,the gas is transferred downwardly to the first outlet chamber 166through the second perforation 164. In response to the downward gas, thevalve plate 17 corresponding to the first outlet chamber 166 is alsosubjected to the downward curvy deformation. Consequently, the valveopening 170 of the valve membrane 17 is correspondingly opened to thedownward side. Under this circumstance, the gas is transferred from thefirst outlet chamber 166 to the second outlet chamber 184 through thevalve opening 170. Then, the gas is transferred to the outlet structure19 through the outlet perforation 182 and then transferred to theequipment which is in communication with the outlet structure 19.Consequently, the purpose of collecting the gas pressure is achieved.

Hereinafter, the gas-releasing operation of the miniature valve device1B will be illustrated with reference to FIG. 6B. For performing thegas-releasing operation, the user may adjust the amount of the gas to befed into the miniature fluid control device 1A, so that the gas is nolonger transferred to the gas-collecting chamber 162. Alternatively, incase that the inner pressure of the equipment which is in communicationwith the outlet structure 19 is higher than the ambient air pressure,the gas-releasing operation may be performed. Under this circumstance,the gas is transferred from the outlet structure 19 to the second outletchamber 184 through the outlet perforation 182. Consequently, the volumeof the second outlet chamber 184 is expanded, and the flexible valveplate 17 corresponding to the second outlet chamber 184 is subjected tothe upward curvy deformation. In addition, the valve plate 17 is inclose contact with the gas collecting plate 16. Consequently, the valveopening 170 of the valve plate 17 is closed by the gas collecting plate16. Moreover, the gas collecting plate 16 has the raised structure 167corresponding to the first outlet chamber 166. Due to the arrangement ofthe raised structure 167, the flexible valve plate 17 can be bentupwardly more quickly. Moreover, the raised structure 167 can provide apre-force to achieve a good sealing effect of the valve opening 170.Since the valve opening 170 of the valve plate 17 is contacted with andclosed by the raised structure 167, the gas in the second outlet chamber184 will not be reversely returned to the first outlet chamber 166.Consequently, the efficacy of avoiding gas leakage is enhanced.Moreover, since the gas in the second outlet chamber 184 is transferredto the second pressure-releasing chamber 183 through the communicationchannel 185, the volume of the second pressure-releasing chamber 183 isexpanded. Consequently, the valve plate 17 corresponding to the secondpressure-releasing chamber 183 is also subjected to the upward curvydeformation. Since the valve plate 17 is no longer in contact with thefirst end of the pressure-releasing perforation 181, thepressure-releasing perforation 181 is opened. Under this circumstance,the gas in the second pressure-releasing chamber 183 is outputtedthrough the pressure-releasing perforation 181. Consequently, thepressure of the gas is released. Similarly, due to the convex structure181 a beside the pressure-releasing perforation 181 or theposition-limiting structure 188 within the second pressure-releasingchamber 183, the flexible valve plate 17 can be subjected to the upwardcurvy deformation more quickly. Consequently, the pressure-releasingperforation 181 can be quickly opened. After the gas-releasing operationin one direction is performed, the gas within the equipment which is incommunication with the outlet structure 19 is partially or completelyexited to the surrounding. Under this circumstance, the pressure of theequipment is reduced.

FIGS. 7A to 7E schematically illustrate the gas-collecting actions ofthe miniature pneumatic device of FIG. 2A. Please refer to FIGS. 1A, 2Aand 7A to 7E. As shown in FIG. 7A, the miniature pneumatic device 1comprises the miniature fluid control device 1A and the miniature valvedevice 1B. As mentioned above, the gas inlet plate 11, the resonanceplate 12, the piezoelectric actuator 13, the first insulation plate 141,the conducting plate 15, the second insulation plate 142 and the gascollecting plate 16 of the miniature fluid control device 1A are stackedon each other sequentially. There is a gap g0 between the resonanceplate 12 and the piezoelectric actuator 13. Moreover, the first chamber121 is formed between the resonance plate 12 and the piezoelectricactuator 13. The valve plate 17 and the gas outlet plate 18 of theminiature valve device 1B are stacked on each other and disposed underthe gas collecting plate 16 of the miniature fluid control device 1A.The gas-collecting chamber 162 is arranged between the gas collectingplate 16 and the piezoelectric actuator 13. The first pressure-releasingchamber 165 and the first outlet chamber 166 are formed in the secondsurface 161 of the gas collecting plate 16. The secondpressure-releasing chamber 183 and the second outlet chamber 184 areformed in the first surface 180 of the gas outlet plate 18. In anembodiment, the operating frequency of the miniature pneumatic device 1is in the range between 27 kHz and 29.5 kHz, and the operating voltageof the miniature pneumatic device 1 is in the range between ±10V and±16V. Moreover, due to the arrangements of the plural pressure chambers,the actuation of the piezoelectric actuator 13 and the vibration of theplate 12 and the valve plate 17, the gas can be transferred downwardly.

As shown in FIG. 7B, the piezoelectric actuator 13 of the miniaturefluid control device 1A is vibrated downwardly in response to theapplied voltage. Consequently, the gas is fed into the miniature fluidcontrol device 1A through the at least one inlet 110 of the gas inletplate 11. The gas is sequentially converged to the central cavity 111through the at least one convergence channel 112 of the gas inlet plate11, transferred through the central aperture 120 of the resonance plate12, and introduced downwardly into the first chamber 121.

As the piezoelectric actuator 13 is actuated, the resonance of theresonance plate 12 occurs. Consequently, the resonance plate 12 is alsovibrated along the vertical direction in the reciprocating manner. Asshown in FIG. 7C, the resonance plate 12 is vibrated downwardly andcontacted with the bulge 130 c of the suspension plate 130 of thepiezoelectric actuator 13. Due to the deformation of the resonance plate12, the volume of the chamber corresponding to the central cavity 111 ofthe gas inlet plate 11 is expanded but the volume of the first chamber121 is shrunken. Under this circumstance, the gas is pushed towardperipheral regions of the first chamber 121. Consequently, the gas istransferred downwardly through the vacant space 135 of the piezoelectricactuator 13. Then, the gas is transferred to the gas-collecting chamber162 between the miniature fluid control device 1A and the miniaturevalve device 1B. Then, the gas is transferred downwardly to the firstpressure-releasing chamber 165 and the first outlet chamber 166 throughthe first perforation 163 and the second perforation 164, which are incommunication with the gas-collecting chamber 162. Consequently, whenthe resonance plate 12 is vibrated along the vertical direction in thereciprocating manner, the gap g0 between the resonance plate 12 and thepiezoelectric actuator 13 is helpful to increase the amplitude of theresonance plate 12. That is, due to the gap g0 between the resonanceplate 12 and the piezoelectric actuator 13, the amplitude of theresonance plate 12 is increased when the resonance occurs.

As shown in FIG. 7D, the resonance plate 12 of the miniature fluidcontrol device 1A is returned to its original position, and thepiezoelectric actuator 13 is vibrated upwardly in response to theapplied voltage. The difference x between the gap g0 and the vibrationdisplacement d of the piezoelectric actuator 13 is given by a formula:x=g0−d. A series of tests about the maximum output pressure of theminiature pneumatic device 1 corresponding to different values of x areperformed. The operating frequency of the miniature pneumatic device 1is in the range between 27 kHz and 29.5 kHz, and the operating voltageof the miniature pneumatic device 1 is in the range between ±10V and±16V. In case that x=1˜5 μm, the maximum output pressure of theminiature pneumatic device 1 is at least 300 mmHg. Consequently, thevolume of the first chamber 121 is also shrunken, and the gas iscontinuously pushed toward peripheral regions of the first chamber 121.Moreover, the gas is continuously transferred to the gas-collectingchamber 162, the first pressure-releasing chamber 165 and the firstoutlet chamber 166 through the vacant space 135 of the piezoelectricactuator 13. Consequently, the pressure in the first pressure-releasingchamber 165 and the first outlet chamber 166 will be graduallyincreased. In response to the increased gas pressure, the flexible valveplate 17 is subjected to the downward curvy deformation. Consequently,the valve plate 17 corresponding to the second pressure-releasingchamber 183 is moved downwardly and contacted with the convex structure181 a corresponding to the first end of the pressure-releasingperforation 181. Under this circumstance, the pressure-releasingperforation 181 of the gas outlet plate 18 is closed. In the secondoutlet chamber 184, the valve opening 170 of the valve plate 17corresponding to the outlet perforation 182 is opened downwardly. Then,the gas within the second outlet chamber 184 is transferred downwardlyto the outlet structure 19 through the outlet perforation 182 and thentransferred to the equipment which is in communication with the outletstructure 19. Consequently, the purpose of collecting the gas pressureis achieved.

Then, as shown in FIG. 7E, the resonance plate 12 of the miniature fluidcontrol device 1A is vibrated upwardly. Under this circumstance, the gasin the central cavity 111 of the gas inlet plate 11 is transferred tothe first chamber 121 through the central aperture 120 of the resonanceplate 12, and then the gas is transferred downwardly to the gascollecting plate 16 through the vacant space 135 of the piezoelectricactuator 13. As the gas pressure is continuously increased along thedownward direction, the gas is continuously transferred to thegas-collecting chamber 162, the second perforation 164, the first outletchamber 166, the second outlet chamber 184 and the outlet perforation182 and then transferred to the equipment which is in communication withthe outlet structure 19. In other words, the pressure-collectingoperation is triggered by the pressure difference between the ambientpressure and the inner pressure of the equipment.

FIG. 8 schematically illustrate the gas-releasing actions or thepressure-reducing actions of the miniature pneumatic device of FIG. 1A.In case that the inner pressure of the equipment which is incommunication with the outlet structure 19 is higher than the ambientair pressure, the gas-releasing operation (or a pressure-reducingoperation) may be performed. As mentioned above, the user may adjust theamount of the gas to be fed into the miniature fluid control device 1A,so that the gas is no longer transferred to the gas-collecting chamber162. Under this circumstance, the gas is transferred from the outletstructure 19 to the second outlet chamber 184 through the outletperforation 182. Consequently, the volume of the second outlet chamber184 is expanded, and the flexible valve plate 17 corresponding to thesecond outlet chamber 184 is bent upwardly. In addition, the valve plate17 is in close contact with the raised structure 167 corresponding tothe first outlet chamber 166. Since the valve opening 170 of the valveplate 17 is closed by the raised structure 167, the gas in the secondoutlet chamber 184 will not be reversely returned to the first outletchamber 166. Moreover, the gas in the second outlet chamber 184 istransferred to the second pressure-releasing chamber 183 through thecommunication channel 185, and then the gas in the secondpressure-releasing chamber 183 is transferred to the pressure-releasingperforation 181. Under this circumstance, the gas-releasing operation isperformed. After the gas-releasing operation of the miniature valvedevice 1B in one direction is performed, the gas within the equipmentwhich is in communication with the outlet structure 19 is partially orcompletely exited to the surrounding. Under this circumstance, the innerpressure of the equipment is reduced.

The performance data of the miniature pneumatic device with differentsizes of square suspension plates are listed in Table 3.

TABLE 3 Side length of square suspension plate 7.5 mm 8 mm 8.5 mm 10 mm12 mm 14 mm Frequency 28 kHz 27 kHz 27 kHz 18 kHz 15 kHz 15 kHz Maximum400 400 320 300 250 200 output MmHg mmHg mmHg mmHg mmHg mmHg pressureDefect rate 1/25 = 1/25 = 3/25 = 10/25 = 12/25 = 15/25 = 4% 4% 12% 40%48% 60%

The results of the above table are obtained by testing 25 samples of theminiature pneumatic device with different sizes of square suspensionplates. The side length of the square suspension plate is in the rangebetween 7.5 mm and 14 mm. As the side length of the square suspensionplate is decreased, the yield and the maximum output pressure are bothincreased. The optimized side length of the square suspension plate isin the range between 7.5 mm and 8.5 mm. The operating frequencycorresponding to the optimized side length is in the range between 27kHz and 29.5 kHz, and the maximum output pressure is at least 300 mmHg.It is presumed that the deformation amount in the horizontal directionis reduced in response to the vertical vibration of the suspensionplate. That is, the kinetic energy in the vertical direction can beeffectively utilized. Moreover, as the side length of the suspensionplate is decreased, the assembling error in the vertical direction isalso decreased. Consequently, the collision interference between thesuspension plate and the resonance plate or other component can bereduced, and a specified distance between the suspension plate and theresonance plate can be maintained. Under this circumstance, the productyield is enhanced, and the maximum output pressure is increased.Moreover, as the size of the suspension plate is reduced, the size ofthe piezoelectric actuator can be correspondingly reduced. Since thepiezoelectric actuator is not readily inclined during vibration, thevolume of the gas channel is reduced and the efficacy of pushing orcompressing the gas is increased. Consequently, the miniature pneumaticdevice of the present invention has enhanced performance and small size.In case that the suspension plate and the piezoelectric ceramic plate ofthe piezoelectric actuator are larger, the suspension plate is readilysuffered from distortion during vibration because the rigidity of thesuspension plate is deteriorated. If the distortion of the suspensionplate occurs, the collision interference between the suspension plateand the resonance plate or other component is increased and thus thenoise is generated. The noise problem may result in the defectiveproduct. That is, as the size of the suspension plate and the size ofthe piezoelectric ceramic plate are increased, the defect rate of theminiature pneumatic device is increased. By reducing the size of thesuspension plate and the size of the piezoelectric ceramic plate, theperformance of the miniature pneumatic device is increased, the noise isreduced, and the defect rate is reduced.

The fact that the size reduction of the suspension plate increases theperformance and maximum output pressure is realized according to theresults of experiments rather than theoretical mathematic formulae.

After the miniature fluid control device 1A and the miniature valvedevice 1B are combined together, the total thickness of the miniaturepneumatic device 1 is in the range between 2 mm and 6 mm. Since theminiature pneumatic device is slim and portable, the miniature pneumaticdevice is suitably applied to medical equipment or any other appropriateequipment.

From the above descriptions, the present invention provides theminiature pneumatic device. The miniature pneumatic device comprises theminiature fluid control device and the miniature valve device. After thegas is fed into the miniature fluid control device through the inlet,the piezoelectric actuator is actuated. Consequently, a pressuregradient is generated in the fluid channels of the miniature fluidcontrol device and the gas-collecting chamber to facilitate the gas toflow to the miniature valve device at a high speed. Moreover, due to theone-way valve plate of the miniature valve device, the gas istransferred in one direction. Consequently, the pressure of the gas isaccumulated to any equipment that is connected with the outletstructure. For performing a gas-releasing operation (or apressure-reducing operation), the user may adjust the amount of the gasto be fed into the miniature fluid control device, so that the gas is nolonger transferred to the gas-collecting chamber. Under thiscircumstance, the gas is transferred from the outlet structure to thesecond outlet chamber of the miniature valve device, then transferred tothe second pressure-releasing chamber through the communication channel,and finally exited from the pressure-releasing perforation. By theminiature pneumatic device of the present invention, the gas can bequickly transferred while achieving silent efficacy. Moreover, due tothe special configurations, the miniature pneumatic device of thepresent invention has small volume and small thickness. Consequently,the miniature pneumatic device is portable and applied to medicalequipment or any other appropriate equipment. In other words, theminiature pneumatic device of the present invention has industrialvalues.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A miniature pneumatic device, comprising: aminiature fluid control device comprising: a gas inlet plate comprisingat least one inlet, at least one convergence channel and a centralcavity, wherein a convergence chamber is defined by the central cavity,wherein after a gas is introduced into the at least one convergencechannel through the at least one inlet, the gas is guided by the atleast one convergence channel and converged to the convergence chamber;a resonance plate having a central aperture corresponding to theconvergence chamber of the gas inlet plate; a piezoelectric actuatorcomprising a suspension plate, an outer frame and a piezoelectricceramic plate, wherein the suspension plate and the outer frame areconnected with each other through at least one bracket, and thepiezoelectric ceramic plate is attached on a first surface of thesuspension plate; and a gas collecting plate comprising a firstperforation, a second perforation, a first pressure-releasing chamber, afirst outlet chamber and a fiducial surface, wherein the gas collectingplate further comprises a raised structure corresponding to the firstoutlet chamber, the raised structure is located at a level higher thanthe fiducial surface of the gas collecting plate, the first perforationis in communication with the first pressure-releasing chamber, and thesecond perforation is in communication with the first outlet chamber,wherein the gas inlet plate, the resonance plate, the piezoelectricactuator and the gas collecting plate are stacked on each othersequentially, and a gap g0 is formed between the resonance plate and thepiezoelectric actuator to define a first chamber, wherein a difference xbetween the gap g0 and a vibration displacement d of the piezoelectricactuator is given by a formula: x=g0−d, and an output pressure of thegas is generated when x=1 μm to 5 μm, wherein after the gas is fed intothe miniature fluid control device through the at least one inlet of thegas inlet plate, the gas is sequentially converged to the central cavitythrough the at least one convergence channel, transferred through thecentral aperture of the resonance plate, introduced into the firstchamber, transferred downwardly through a vacant space between the atleast one bracket of the piezoelectric actuator, and exited from theminiature fluid control device; and a miniature valve device comprising:a valve plate having a valve opening, wherein a thickness of the valveplate is in a range between 0.1 mm and 0.3 mm; and a gas outlet platecomprising a pressure-releasing perforation, an outlet perforation, asecond pressure-releasing chamber, a second outlet chamber, at least oneposition-limiting structure and a fiducial surface, wherein a convexstructure is located beside an end of the pressure-releasingperforation, the convex structure is located at a level higher than thefiducial surface of the gas outlet plate, the outlet perforation is incommunication with the second outlet chamber, the at least oneposition-limiting structure is disposed within the secondpressure-releasing chamber, a thickness of the position-limitingstructure is in a range between 0.2 mm and 0.5 mm, and the gas outletplate further comprises a communication channel between the secondpressure-releasing chamber and the second outlet chamber, wherein thegas collecting plate, the valve plate and the gas outlet plate arecombined together, the pressure-releasing perforation of the gas outletplate is aligned with the first perforation of the gas collecting plate,the second pressure-releasing chamber of the gas outlet plate is alignedwith the first pressure-releasing chamber of the gas collecting plate,and the second outlet chamber of the gas outlet plate is aligned withthe first outlet chamber of the gas collecting plate, wherein the valveplate is arranged between the gas collecting plate and the gas outletplate for blocking communication between the first pressure-releasingchamber and the second pressure-releasing chamber, and the valve openingof the valve plate is arranged between the second perforation and theoutlet perforation, wherein after the gas is downwardly transferred fromthe miniature fluid control device to the miniature valve device, thegas is introduced into the first pressure-releasing chamber and thefirst outlet chamber through the first perforation and the secondperforation, and the valve plate is quickly contacted with the convexstructure of the gas outlet plate to provide a pre-force to tightlyclose the pressure-releasing perforation, and the gas within the firstoutlet chamber is further transferred to the outlet perforation throughthe valve opening of the valve plate, so that a pressure-collectingoperation is performed, wherein while a pressure-releasing operation isperformed, the gas is transferred from the outlet perforation to thesecond outlet chamber to move the valve plate, the valve opening of thevalve plate is contacted with and closed by the gas collecting plate,the at least one position-limiting structure assists in supporting thevalve plate to avoid collapse of the valve plate, the gas is transferredfrom the second outlet chamber to the second pressure-releasing chamberthrough the communication channel, the valve plate corresponding to thesecond pressure-releasing chamber is moved, and the gas is exited fromthe pressure-releasing perforation.
 2. The miniature pneumatic deviceaccording to claim 1, wherein an operating frequency of the miniaturepneumatic device is in a range between 27 kHz and 29.5 kHz, and anoperating voltage of the miniature pneumatic device is in a rangebetween ±10V and ±16V.
 3. The miniature pneumatic device according toclaim 1, wherein when x=5 μm to 10 μm, the output pressure is equal to250 mmHg.
 4. The miniature pneumatic device according to claim 1,wherein when x=10 μm to 15 μm, the output pressure is equal to 150 mmHg.5. The miniature pneumatic device according to claim 1, wherein a lengthof the suspension plate is in a range between 7.5 mm and 12 mm, a widthof the suspension plate is in a range between 7.5 mm and 12 mm, and athickness of the suspension plate is in a range between 0.1 mm and 0.4mm.
 6. The miniature pneumatic device according to claim 5, wherein thelength of the suspension plate is in a range between 7.5 mm and 8.5 mm,the width of the suspension plate is in a range between 7.5 mm and 8.5mm, and the thickness of the suspension plate is 0.27 mm.
 7. Theminiature pneumatic device according to claim 1, wherein a length of thepiezoelectric ceramic plate is not larger than a length of thesuspension plate, the length of the piezoelectric ceramic plate is in arange between 7.5 mm and 12 mm, a width of the piezoelectric ceramicplate is in a range between 7.5 mm and 12 mm, a thickness of thepiezoelectric ceramic plate is in a range between 0.05 mm and 0.3 mm,and a length/width ratio of the piezoelectric ceramic plate is in arange between 0.625 and 1.6.
 8. The miniature pneumatic device accordingto claim 7, wherein the length of the piezoelectric ceramic plate is ina range between 7.5 mm and 8.5 mm, the width of the piezoelectricceramic plate is in a range between 7.5 mm and 8.5 mm, and the thicknessof the piezoelectric ceramic plate is 0.10 mm.
 9. The miniaturepneumatic device according to claim 1, wherein the suspension platefurther comprises a bulge, and the bulge is formed on a second surfaceof the suspension plate, wherein the bulge is a circular convexstructure, and a diameter of the bulge is 0.55 times as large as a shortside length of the suspension plate.
 10. The miniature pneumatic deviceaccording to claim 1, wherein the resonance plate is made of copper, anda thickness of the resonance plate is in a range between 0.03 mm and0.08 mm.
 11. A miniature pneumatic device, comprising: a miniature fluidcontrol device comprising: a gas inlet plate; a resonance plate; apiezoelectric actuator comprising a suspension plate, wherein a lengthof the suspension plate is in a range between 7.5 mm and 12 mm, and awidth of the suspension plate is in a range between 7.5 mm and 12 mm;and a gas collecting plate comprising a first perforation, a secondperforation, a first pressure-releasing chamber and a first outletchamber, wherein the gas inlet plate, the resonance plate, thepiezoelectric actuator and the gas collecting plate are stacked on eachother sequentially, and a gap g0 is formed between the resonance plateand the piezoelectric actuator to define a first chamber, and agas-collecting chamber is formed between the piezoelectric actuator andthe gas collecting plate, wherein a difference x between the gap g0 anda vibration displacement d of the piezoelectric actuator is given by aformula: x=g0−d, and an output pressure of gas is generated when x=1 μmto 5 μm, wherein after the gas is fed into the miniature fluid controldevice through the gas inlet plate, the gas is transferred through theresonance plate, introduced into the first chamber, and transferreddownwardly to the gas-collecting chamber; and a miniature valve devicecomprising: a valve plate having a valve opening; and a gas outlet platecomprising a pressure-releasing perforation, an outlet perforation, asecond pressure-releasing chamber and a second outlet chamber, whereinthe gas collecting plate, the valve plate and the gas outlet plate arecombined together, wherein after the gas is downwardly transferred fromthe gas-collecting chamber to the miniature valve device, the gas istransferred through the first perforation, the second perforation, thefirst pressure-releasing chamber, the first outlet chamber, the secondpressure-releasing chamber, the second outlet chamber, thepressure-releasing perforation and the outlet perforation, wherein thegas is transferred in one direction, and the valve opening of the valveplate is correspondingly opened or closed, so that a pressure-collectingoperation or a pressure-releasing operation is selectively performed.12. The miniature pneumatic device according to claim 11, wherein thegas inlet plate comprises at least one inlet, at least one convergencechannel and a central cavity, wherein after the gas is introduced intothe at least one convergence channel through the at least one inlet, thegas is guided by the at least one convergence channel and converged tothe central cavity, wherein the resonance plate has a central aperturecorresponding to the central cavity of the gas inlet plate, and thepiezoelectric actuator comprises the suspension plate, an outer frameand a piezoelectric ceramic plate, wherein the suspension plate and theouter frame are connected with each other through at least one bracket,and the piezoelectric ceramic plate is attached on a first surface ofthe suspension plate.
 13. The miniature pneumatic device according toclaim 11, wherein the valve plate is arranged between the gas collectingplate and the gas outlet plate.
 14. The miniature pneumatic deviceaccording to claim 11, wherein when x=5 μm to 10 μm, the output pressureis equal to 250 mmHg.
 15. The miniature pneumatic device according toclaim 11, wherein when x=10 μm to 15 μm, the output pressure is equal to150 mmHg.
 16. The miniature pneumatic device according to claim 12,wherein a length of the piezoelectric ceramic plate is not larger than alength of the suspension plate, the length of the piezoelectric ceramicplate is in a range between 7.5 mm and 12 mm, a width of thepiezoelectric ceramic plate is in a range between 7.5 mm and 12mm, athickness of the piezoelectric ceramic plate is in a range between 0.05mm to 0.3 mm, and a length/width ratio of the piezoelectric ceramicplate is in a range between 0.625 and 1.6.
 17. The miniature pneumaticdevice according to claim 12, wherein a thickness of the suspensionplate is 0.27 mm.
 18. A miniature pneumatic device, comprising: aminiature fluid control device comprising a gas inlet plate, a resonanceplate, a piezoelectric actuator and a gas collecting plate, wherein thepiezoelectric actuator comprises a suspension plate having a length in arange between 7.5 mm and 12 mm and a width in a range between 7.5 mm and12 mm, wherein the gas inlet plate, the resonance plate, thepiezoelectric actuator and the gas collecting plate are stacked on eachother sequentially, and a gap g0 is formed between the resonance plateand the piezoelectric actuator to define a first chamber, wherein adifference x between the gap g0 and a vibration displacement d of thepiezoelectric actuator is given by a formula: x=g0−d, and an outputpressure of gas is generated when x=1 μm to 5 μm, wherein after the gasis fed into the miniature fluid control device through the gas inletplate, the gas is transferred through the resonance plate, introducedinto the first chamber, and exited from the miniature fluid controldevice; and a miniature valve device comprising a valve plate having avalve opening and a gas outlet plate, wherein the valve plate has avalve opening, and the gas collecting plate, the valve plate and the gasoutlet plate are combined together, wherein after the gas is transferredfrom the miniature fluid control device to the miniature valve device, apressure-collecting operation or a pressure-releasing operation isselectively performed.
 19. The miniature pneumatic device according toclaim 18, wherein a gas-collecting chamber is formed between thepiezoelectric actuator and the gas collecting plate, and the gas isexited from the miniature fluid control device through thegas-collecting chamber.
 20. The miniature pneumatic device according toclaim 18, wherein each of the gas collecting plate and the gas outletplate comprises at least two perforations and at least two chambers,wherein the gas is transferred in one direction, and the valve openingof the valve plate is correspondingly opened or closed.